The invention relates to an air filter system, particularly for commercial vehicles. In addition, this invention also relates to a main filter element and a secondary filter element for use in the air filter system of the invention and to a method of purifying intake air using the air filter system according to the invention.
The air filter systems known in the prior art for internal combustion engines are mounted mainly near the engine, usually in the engine compartment. However, it is becoming increasingly more difficult to install the air filter system in this area because the installation space available for this purpose is becoming smaller and smaller. In particular in commercial vehicles, especially in tractors, the available space is very limited due to the extra functional elements such as hydraulic and pneumatic elements installed in the engine compartment, and access to these systems is often hindered due to an air filter system located in the engine compartment near the engine. In addition, the intake point is often located in the dirty area of the vehicle, i.e., resulting in an elevated particle burden on the air filter and thereby reducing the lifetime of the air filter.
In this regard, German Utility Model No. 79 02 819 describes a proposed intake air purifying element as an external element for mounting on the body of a truck, whereby the element contains a prefilter and a water separator, a cyclone and air filter. However, this design is limited individually to the body of the various trucks and is thus greatly restricted with regard to free placement and in many cases, e.g., in agricultural machines with their special bodies cannot be used at all.